Percussion tools for wells



Aug. 14, 1956 R. BASSINGER PERCUSSION TOOLS FOR WELLS 3 Sheets-Sheei l Filed ocr. 5, 1950 Mu Mid Aug. 14, 1956 R. BASSINGER 2,758,817

PERCUSSION TooLs FOR WELLS Filed Cer. s, 195o 5 shets-sneet 2 INVENTOR osszasslyelf ATTORNEYS BY Jwwwmwf//w 3 Sheets-Sheet C6 INVENTOR R. BASSINGER PERCUSSION TOOLS FOR WELLS Aug. 14, 1956 Filed oct. 3, 195o United States Patent PERCUSSION TOOLS FOR WELLS Ross Bassinger, New Braunfels, Tex.

Application October 3, 1950, Serial No. 188,165

4 IClaims. (Cl. Z55-4.4)

This invention relates to new and useful improvements in percussion tool-s for wells.

Recently much emphasis has been placed in the drilling industry on percussion tools operating under the inuence of iluid control valves. These valves are located within a housing forming a portion of the drill string. They are usually comprised of at least two reciprocating elements which alternately engage and disengage under the influence of the pressurized mud fluid. This valve action results in intermittent percussion blows delivered to a hammer and ultimately to an anvil located adjacent the drill bit. The combination of rotating movement of the bit and rapid percussion blows applied thereto results in a very ecient drilling operation.

The two elements comprising the valve reciprocate at very high speed, and both come to abrupt stops when -at the end of their strokes. One of the elements is usually in the form of a sleeve which is connected to the hammer and called the hammer sleeve, and the other in the form of a piston called the control piston for controlling the operation of the valve. The hammer sleeve is travelling at a very high speed when it suddenly strikes the anvil and due to its loss of inertia and the influence of the spring against which it has, up to this point, been operating, reverses its direction. The control piston travel a portion of the hammer sleeve stroke in engagement with the hammer sleeve and then comes to an abrupt stop when it reaches the end of its own stroke which is usually determined by 4a. stop. It is evident then that the abrupt stop of the control piston when at the end of its stroke will ultimately cause damage to the control piston. It is, therefore, an object of this invention to provide a means of helping to arrest the violent downward movement of the control piston to greatly reduce the frequency of mechanical failure of both the control piston and the control piston stop.

When the hammer sleeve has reached the end of its stroke and has imparted its energy to the anvil, it then returns in an upward direction under the influence of a spring mounted in tension within the housing. Toward the end of its upward stroke it again engages the control piston. It is another object of this invention to provide means to help arrest the upward movement of the hammer sleeve after it has again contacted the control piston and to permit overtravel ot' these two elements when they have again come into telescopic relation. This will greatly reduce the amount of mechanical wear due to the telescoping engagement or these elements.

Another object of this invention is to provide means of accelerating the speed of the hammer sleeve to increase the amount of energy imparted to the anvil when the hammer delivers its impact blow to the anvil.

Other and further objects of this invention will be apparent from the following description of the drawings:

Figure l is a longitudinal View partly in elevation and partly in section of a percussion tool constructed in accordance with this invention;

Figure 2 is a longitudinal view in section of a percus- 2,758,817 Patented Aug. 14, 1956 ICC sion tool constructed in accordance with this invention, and showing the reciprocating elements of the control valve in disengaged relationship;

Figure 3 is a longitudinal vieW in section similar to Figure 2 but showing the elements of the control valve in different positions;

Figure 4 is a longitudinal view in section showing the elements of the valve in st-ill another position;

Figures 5, 6 and 7 are figures taken along the lines 5-5, 6 6, and 7-7 of Figure 2;

Figure 8 is a longitudinal view in section of the percussion tool which is another embodiment of this invention;

Figure 9 is a longitudinal View in section of a percussion tool which is still another modication of this invention;

Figures l0 and 11 are views taken along the lines 10-10 and 11-11 of Figure 8; and

Figure 12 is a view taken along the line 12-12 of Figure 9.

With reference to Figure l, wherein is shown partly in elevation and partly in section the entire tool assembly, the letter A represents the tool housing in which are mounted all of the elements of the percussion tool. Mud tluid is admitted in the top of the tool and escapes from the bottom. The flow of mud uid through the housing is controlled by v-alve generally designated by the letter B. The lower element of the valve, in this instance being the hammer sleeve, is connected to a hammer designated by the letter C which imparts impact blows under the intluence of the operation of the reciprocating elements of the valve B to an anvil generally designated by the letter D. The bit carrier assembly which forms the lower part of the anvil D is provided with threaded socket E for the reception therein of the drill bit. The anvil is by some means such as a splined connection, relatively movable in a vertical direction with respect to the housing.

When the percussion tool, which is attached to the lower end of the drill string, is first lowered into the hole, the mud lluid is not under pressure and the elements of the control valve are in the positions indicated in Figure 2. The control or valve rod guide assembly 20 which receives the control or Valve rod 2l is in its uppermost position in the tool housing 22. The assembly is held in this position by a spring 23 which is mounted between the guide lugs 24 and a ring 25 mounted -in the lower part of the housing. The spring functions to keep the control rod guide in the position shown in this gure, only when the pumps are stopped and the tool is being withdrawn from the hole or is being placed in the hole. The purpose of this spr-ing is to enable dry pipe to be pulled when coming out of the hole as well as to keep the control rod assembly from operating as a valve when going into the hole. When the pumps are stopped and there is no pressure drop across the control rod guide, this enlarged spring has suiiicient force to raise the entire guide assembly to its uppermost position as shown in Figure 2. The guide lugs are flush with the depending skirt 26 of the tool joint 27. In this upper posit-ion the con-trol piston or valve plug 28 mounted at the lower end of the rod 21 is raised up to a point where the hammer (C in Figure 1) cannot raise high enough so that the control piston will seat in a valve seat 29a of a hammer sleeve 29. The hammer is attached to this hammer sleeve in the lower portion of the tool housing in a manner similar to that disclosed in this applicants copending application Serial No. 143,898, filed February 13, 1950, now U. S. Letters Patent 2,665,115.

When the percussion tool is placed in the hole and the elements are in relation to each other as shown in Figure 2, mud enters the tool at the top and seats the control guide assembly on a shoulder 30 for-med in the housing as shown in Figure 3. At this time the control piston 28 enters the'hammer sleeve 29, blocking the circulation of the mud fluid and forcingthe hammer in a downward direction. The pressure differential across the .control piston causes it to stay seated on topvof the hammer sleeve until the stop 31 of the control rod 21 strikes the exhaust spacing washer 32 thus stopping the downward move* ment of the contro-l rod.

The position of the elements immediately after the unseating of the control piston and hammer sleeve is shown in Figure 4. The hammer (C in ifgure l) continues down until it strikes the anvil (D in Figure 1), thus allowing the mud to exhaust through the bore 33 in the hammer sleeve 29, releasingy the differential pressure across control piston 23 so that the control rod 21 is immediately forced to its uppermost position by the control spring 21a helically wound about the upper portion of the rod 21. This spring is mounted between a cap 22a on top of the rod 21 and a strike pad 3ft. The hammer then returns in an upward direction due to the force of the main hammer spring (F in Figure 1) mounted above the hammer sleeve in a manner disclosed by this applicant in his copending application Serial No. 143,898 plus the force of the rebound olf the anvil. As thehammer nears the top of its stroke the control piston 28 again enters its seat on top of the hammer sleeve Z9 and the hammer sleeve and control piston both continue up until their inertia is arrested by the force of the mud again acting across the hammer piston. This overtravel is provided in that the strike pad 34 is free to rise in the control rod guide.

Radial slots 35 provided in the top of the strike pad ange 36 keep this ange from acting as a vbar against the pin 26 when going in the hole, and the circulation is upward. The length of the hammer stroke may be varied by putting in strike pads of different lengths, and the exhaust may be varied oy putting in exhaust spacing washers of different heights.

Referring again to Figure 2 and to Figures 5 to 7, it will be noted that the control rod 21 has a tapered thread lower portion 37 and the control piston has a complementary threaded recess 38 to receive the threaded portion ofthe control rod. The control piston is also provided with a ange portion 39 which tapers off at its lower extremity to a diameter which can slidably fit within the bore 33 of the hammer sleeve 29. It will be noted that this portion of the control piston is provided with an annular groove 4i) in which is placed a ring 4i of rubberized material. This is for the purpose of reducing the wear resulting from the telescoping of the control piston and hammer sleeve. The hammer sleeve 29 as shown in this gure has a threaded recess 42 in which is threaded the upper portion 43 of the hammer sleeve. The construction of this portion is made thusly because the upper portion of the hammer sleeve usually wears out at a much more rapid rate than any other portion, and provision is by this manner made for replacement of a part of the hammer sleeve without the necessity of replacing it all.

As shown in Figure 2, the lower portion 44 of the tool housing is connected to the main portion of the tool housing 22 by a tool joint generally designated by numeral 45. The hammer sleeve travels in this lower portion 44 and its stroke is guided therein by an arrangement such as a key fixed to the lower portion of the hammer sleeve and riding in guide slots provided in a spacer ring rfi-6. The key and guide slots do not form a part of the present invention.

What has been illustrated heretofore is one embodiment of the present invention. The upper element of the valve has been shown to be a control piston and the lower element of the valve a hammer sleeve. It is within the `scope of this invention to reverse the two elements. That is, the control element or upper valve engage.

f piston as well as a reversal assist.

element may be, instead of in the form of a piston, in the form of a sleeve and the lower element vto which the hammer is attached may be in the form of a piston. The interaction of the two elements in such an embodiment is exactly the same. The hammer piston would seat in the control sleeve and the reciprocation of the two would be controlled in the exact same manner as heretofore described.

Another embodiment of the present invention is disclosed in Figures 8, 10 and 11. The lower portion of this embodiment of the percussion tool is the same as that heretofore described with reference to Figures 1 and 2. The upper portion, that is the control piston, is, however, modified from `that shown in Figure 2. When huid is pumped into the bore 47 of the tool joint 43, the control piston r9 is urged in an upward direction by virtue of the fact that the area of the control piston flange 5@ exposed to the pressure of the iluid is greater than the area of the control piston wall 51 of the control piston 49 which is exposed to the same huid. The pressureat these two aforementioned points is only equal as long as the control piston di) is engaged in the hammer sleeve 52. Surge ports 52a expose the outer surface of the control piston 49 and the upper surface of the control piston flange 5i) to the well bore pressure which, of course, is at all times less than the pressure within the drill stem. When the two valve elements are separated, the control piston will rise due to the greater area of the control piston flange Si) than the control piston wall S1. It will rise and compress the spring 53 until a position of equilibrium determined by the size of the spring is reached. The control piston being in this upper position, the hammer spring, not shown, but identical with that shown in Figure 1, raises the hammer sleeve 52 until the control piston head 54 seats itself in the hammer sleeve. A seal 55, usually of rubberized material, engaged in an annular groove of the pilot 56 of the control piston head Ed prevents ieakage of the mud uid down into the bore 57 of the hammer sleeve when the elements are in engaging relation. The control piston head is provided with a face 5S complementary in contour to that of the face 59 of the hammer sleeve. These faces take some vof the landing impact when the two elements With the control piston head seated in the hammer sleeve in nesting relation, the eiective area of the hammer sleeve becomes the cross-sectional diameter of the outside diameter of the hammer sleeve.

Thus the control piston rides part of the way with the hammer stroke or until the control piston comes to a stop on the shoulder 69 formed in the central portion of the tool housing 61. The hammer sleeve continues its downward movement but with an effective area which is less than that during the first part of the stroke. It is apparent, then, that by this arrangement when the hammer offers the most resistance on its upward movement and reversal it has more area exposed to the fluid to assist in reversal. When, however, it is in motion it does not need the increased area and possibly increases in acceleration due to the decreased area when the nesting ceases.

The main purpose of the spring 53 is to act as a reversal assist as well as to permit overtravel of the hammer after contact with the control piston. It serves, then, a dual purpose, to act as a stop for the control The ports 62 in the control piston allow the mud fluid to escape from the bore 63 through these ports into the cavity 64 and down through the bore 157 Iof the hammer sleeve 52.

Another embodiment of the invention is shown in Figures 9 and 12. The tool housing 65 contains the valve having a control sleeve 66 in the upper position and a hammer piston 67 in the lower position. The operation of this embodiment is the same as that illustrated in Figure 8 with the exception that the control sleeve coacts with a male piston instead of a female.

What have been described are preferred embodiments of the invention but it is also contemplated that other embodiments obvious from those presented are included within the scope of the inventive concept. The embodiments are presented by way of illustration and are not meant to limit in any way the scope of the invention.

What is claimed is:

il. In an impact tool of the class having a hammer reciprocally mounted in a housing for striking an anvil carried by the housing and having coacting first and second valve elements carried by the hammer and housing, respectively, to seat and dr-ive the hammer toward the anvil and to open to permit the hammer to move from the anvil, the improvement which comprises the combination therewith of a mounting means for the second valve element carried by the housing for limited movement with respect thereto, means biasing the mounting means away from the hammer, a stop for limiting movement of the mounting means toward the hammer and a restricted iluid passage through the mounting means and forming a part of the fluid passage through the tool so that uid flow through the tool moves the mounting means toward the hammer and against said stop to place the second valve element in coacting position with the first valve element and, upon substantial decrease or cessation of uid ow, said biasing means moves the mounting means away from the hammer to position the second valve element out of coacting position with the first valve element.

2. lIn a percussion well drilling tool having a tubular housing with a drill bit assembly mounted at its lower end for limited vertical movement relative to the housing, an anvil, a hammer within lthe housing mounted for vertical movement from an anvil striking position to an upper position, means biasing said hammer toward said upper position, and a fluid ilow passage extending longitudinally through said hammer, the improvements that comprise a valve which includes a irst element carried by said hammer for movement therewith and a second element, said elements comprising a valve member and a sea-t therefor which coaot to control uid ow through said passage, means mounting said second element in said housing above the hammer, said mounting means being vertically movable, said second element being ventica=lly movable relative to said mounting means, means limiting the downward movement of said mounting means, resilient means biasing said m'ounting means to a position upwardly away from said movement limiting means, means limiting the downward movement of said second element relative to said mounting means, resilient means biasing said second element upwardly away from said downward movement limit to an at-res-t position intermediate the ends of the path of travel of the second element relative to said mounting means, means in said mounting means permitting ilow of drill uid therethrough to establish a flow of fluid through said housing to said hammer passage, said flow of pressure uid coacting with said mounting means to move said mounting means and said second element downwardly from an upper rest position to seat the second element in engagement with the tirs-t element to close off said hammer passage whereby said second element and hammer move unitarily by torce lof said drill iu-id toward said anvil until said second elements downward movement is stopped by its limiting means while Ethe hammer continues its downward movement to strike said anvil, said second element being restored by its biasing means to its said =atrest position, and said hammer is moved up after engaging said anvil by its said hammer biasing means to re-engage said valve elements with each other, again closing oit said hammer passing after which both valve elements continue to move upwardly beyond the point of engagement of said valve elements until such upward movement is arrested by the action of said pressure fluid and said hammer and valve element movement cycle is repeated.

3, A percussion well drilling tool as claimed in claim 2, wherein said second element movement limiting means comprises a stop mounted on said second element and a washer of variable thickness mounted in said mounting means in the path of movement of said stop, said stop and washer coacting to limit the downward travel of said second element.

4. A percussion tool as dened in claim 2, wherein said second element is a valve plug and stem.

References Cited in the iile of this patent UNITED STATES PATENTS 1,861,042 Zublin May 3-1, 1932 2,507,585' Bassinger May 16, 1950 FOREIGN PATENTS 351,457 yItaly May 20, 1937 

